Multi-objective Robust Optimization Design Of Flexible Mechanism Micro-displacement Amplifier

As an important equipment in micro-nano manufacturing and precision processing industry,the micro-displacement amplifier of flexible mechanism is widely used in high-end medical treatment,national defense,aerospace and other cutting-edge fields.Due to its small structure,the structural failure and performance degradation will occur during the service period due to various factors.Aiming at this problem,this research considers to optimize its structure to improve its performance.Taking a certain type of flexible micro-displacement amplifier as the research object,the performance indexes of the original structure were analyzed,and then the original structure was optimized by combining the three aspects of shape optimization,size optimization and robust optimization,so as to improve the performance indexes stably.The main research work are illustrated as follows:(1)To optimize the design of the flexible micro-displacement amplifier,it is necessary to analyze the working principle of the flexible micro-displacement amplifier and determine the benchmark values of each performance index of the original structure under the action of working load.In this research,the performance index values are obtained through three-dimensional software modeling and finite element software simulation instead of real experiments.Provide reference standard for subsequent optimization design.(2)In this research,the optimal performance of flexible micro-displacement amplifier with single hinge structure is studied.In combination with the shape optimization idea,the structure is first split into flexure hinges and rigid beams.The flexure hinges are regarded as replaceable parts,and the structural parameters of rigid beams are taken as fixed values.Then three representative flexure hinges are selected for multi-hinge combination design.Based on the orthogonal experiment,the structural model of flexible micro-displacement amplifier with multi-hinge combination is obtained.The stress amplification ratio index is introduced to evaluate the advantages and disadvantages of each model.Finally,the optimal hinge combination model is selected through range analysis to provide a basis for subsequent parameter optimization design of rigid beams.(3)The optimal performance of the original rigid beam structure of flexible micro-displacement amplifier is studied.Based on the results of multi-hinge combination design and the idea of dimensional optimization,the response surface proxy model is selected to fit the functional relationship between each performance index and the structuralparameters of the rigid beam.Then,based on the mass loss function,the multi-objective optimization problem is integrated into the single-objective normalization problem.Finally,the structural optimization design model of the flexible micro-displacement amplifier is established to obtain the optimal performance index under the condition of minimum overall mass loss.(4)The results of the dual optimization design combined with the idea of structural separation may not be robust and the optimization degree between various performance indicators is difficult to balance.First through integration of the game theory of entropy method and fuzzy analytic hierarchy process comprehensive empowerment of each performance index,at the same time based on dual response surface method to establish a rigid beam structure parameters and the mean and standard deviation of the performance index is considered the target weights of robust optimization model,the final optimization result in the error of the selected interval for the mean and standard deviation test,verify the robust optimization effect,achieve the robust optimization of flexible micro displacement amplifier structure.